The present invention relates to automatic packaging apparatus and machinery for continuously making a chain of wrappers from heat-sealable paper, each wrapper containing a single product. The invention relates in particular to an apparatus for making individual wrappers for filter bags containing products to be infused such as tea, chamomile or other herb teas.
In state-of-the-art packaging technology, wrappers of this kind are made by apparatuses of numerous different kinds. One of these, used for packaging tea bags comprises: a feed device with a pair of motor-driven rollers whose lateral surfaces oppose each other; a station for unwinding a web of heat-sealable paper, from which a first web of paper, used to make the wrapper and having position references impressed on it, is continuously unwound by a feed device; a station for feeding filter bags which continuously receives and feeds out the first web of paper while placing the filter bags on the web in succession and spaced equally apart; a station for feeding a second web of heat-sealable paper, where the second web of paper, fed by the feed device, is laid over the filter bags and moves along continuously together with the first web of paper below it; a sealing station where the two webs of paper are joined crossways and lengthways to form a chain of closed wrappers, each containing a single filter bag.
This apparatus has two separate pairs of motor-driven rollers. The first pair, besides acting as a feed device, seals the webs of paper along their lengthways edges. The second pair of rollers, on the other hand, seals the webs crossways. The apparatus also has a system of opposing conveyor belts designed to place the individual filter bags on the first web in succession and spaced equally apart.
Although this kind of apparatus works correctly, it has the disadvantage of being mechanically very complex which makes it very expensive to construct. Another disadvantage is that this mechanical complexity adversely affects the efficiency of the system to detect and correct the misalignment of the seals using the position references impressed on the first web.
The aim of the present invention is to overcome the disadvantages mentioned above by providing an apparatus that is simple in construction and therefore economical to make.